Rotor assemblies in gas turbine engines typically include a rotor disc which is attached to a driving shaft, with the disc and shaft usually being made of the high strength material, for example titanium or steel. The disc and shaft are generally connected through a bolted joint, a spline attachment, or a curvic coupling, to ensure that the torque is transmitted from the shaft to the rotor disc. However, such connection features usually tend to produce high stress concentrations which may reduce the low cycle fatigue life of the assembly.